Timer for internal-combustion engines



May 3.1927.

S. P. M DONNELL ET AL TIMER FOR INTERNAL COMBUSTION ENGINES Filed March 1926 Patented May 3, 1927.

UNITED STATES PATENT OFFICE.

STEPHEN P. MCDONNELL AND PAUL A. VILLARS, OF DALLAS, TEXAS.

TIMER FOR INTERNAL-COMBUSTION ENGINES.

Application filed March 29, 1926.

This invention relates to improvements in timers for contacts in electrical circuits and has for its object to provide a device of this description which will positively make and break the several contacts in proper timed relation, and so constructed that there will be no lost motion between the contact parts due to wear or the loose fitting thereof.

It is also an object of the invention to provide a timer which will prevent arching at contact points and further to prevent burning and roughness, thereby eliminating the causes of missing at the contact points.

Further objects are to provide a timer which will make a perfect contact at points by taking up loose fitting of parts, thereby making easy starting of engines.

The invention will be fully understood by reference to the following detailed descrip tion, in connection with the accompanying drawings, and wherein- Figure 1 is a front view of a timing de vice constructed in accordance with the invention.

Figure 2 is a side view of the spur gear illustrated in Figure 1, and showing the gear mounted on the cam shaft of an internal combustion engine.

Figure 3 is a perspective View of a sup port for mounting the spur gear.

Proceeding in accordance with the draw ings and wherein numerals are employed to designate the various parts, 1 denotes the shell of the timer and within which is disposed an annular internal gear 2 which forms an insulation medium. This annular gear 2 is stationary and is held in position by the small bolts and nuts 3 and 4, the bolts comprising a part of the contact element for the electrical current, the nuts holding in place the electric wires 5 leading to the battery. ()n the inner end of the con-- (acts or bolts 3 are toothed segments 6, the both of which are alined with the teeth of the annular gear 2. These toothed segments it will be observed are also counter sunk in the annular gear and thus serve to lock the gear in place.

Referring to Figure 2 it will be seen that the cam shaft 7 has a sleeve 8 and upon the latter is mounted a bracket 9. This bracket has an aperture through which a swivel 11 on the sleeve passes. This permits the bracket to swing free on rotation of the cam shaft. The bracket 9 carries a spur gear 12, the pin supporting which is carried in the Serial No. 98,169.

apertures 13. Forming a part of the bracket is a curved arm 14, and on the sleeve 8 is an eyed projection 15. Connected between the projection 15 and arm 14 is a spring 16 for the purpose of providing tension on the spur gear to keep the teeth of the spur gear at all times against the sides of the teeth of the internal annular gear to insure a good electrical contact. 7

In operation of the device, the rotation of he cam shaft 7 will cause the spur gear to be rotated around inside the annular gear 2. As the spur gear 12 comes in contact with the toothed segments or contacts 6 a sparkis produced in the cylinder of the engine. There will be very little wear on the device, and such as there is will be taken up by the spring 16, even though the spur gear teeth become worn to an extent that they might mesh loosely. Further, this spring 16 is so placed that it keeps contact at all times between the sides of the teeth and not the bot tom thereof, thereby eliminating wear of the teeth of the spur gear into the bottom of the annular gear 2. It will also not loose contact at points where needed when used in a motor vehicle while traveling over rough ground or when the vehicle is bounced up and down.

It should be understood also that changes and modifications may be made in the de vice in keeping with the appended claim.

lVhat is claimed is:

A timer for internal combustion engines in combination with the cam shaft thereof, comprising a shell with electrical contact members, an annular toothed rim member on the interior of the shell; the cam shaft of the engine projecting into the shell and having a sleeve mounted on the shaft, said sleeve including a bracket for supporting a minia ture shaft, a spur gear carried on the shaft and in mesh with the annular rim and contact points as the cam shaft rotates; said bracket having formed thereon a curved arm, a spring connected to the arm, the opposite end of the spring connected to said sleeve; said spring for the purpose of holding the spur gear in close contact with the sides of the teeth on said annular rim member and the contacts.

In testimony whereof we afiix our signatures.

STEPHEN P. MODONNELL. PAUL A. VILLARS. 

